A TRANSIT van rated at more than 45 to the gallon will be on the road by the autumn heralding the introduction of a new generation of diesel engines from Ford.

Made in Britain and the product of more than £400 million worth of investment at Ford's research centres at Dunton in Essex and Aachen in Germany, the EcoBlue diesel is not only mean but exceptionally lean.

In the two tonne Transit Ford is claiming an official fuel return on 40.9mpg with emissions of 182g/km while in the lighter Transit Custom the new engine is classified at 46.3mpg, taking its CO2 figure down to 157g/km.

As such the new breed of Transit becomes one of the most economical vans on the market and the EcoBlue has been designed to out-perform the 2.2-litre engine Ford has used since the current van was launched in 2012.

The EcoBlue engine meets all Euro 6 emissions standards and while it is making its debut in the Transit it will feature heavily in all of Ford's future diesel models - and that includes cars, MPVs and SUVs.

To complement the Transit's new eco image, Ford is also introducing a range of new technology to Britain's best loved van as well as tweaking its handling to improve the ride.

Among the new options is rear air suspension which is on top of the Transit's electronic stability systems to counter heavy loads affecting cornering on any of the front, rear or all-wheel-drive set ups.

Ford says the changes are designed to make the Transit as comfortable and refined as a family car and for van man or woman the transformation will be quite remarkable.

Cabin noise has been reduced significantly, there's more feel through the steering and the enhancements to the ride quality are very noticeable.

The result is much more composure on the road and the latest Transit has to be one of the easiest vans to drive.

Other techie systems include crosswind stability control which reduces the effect of buffet from other vehicles or sideways gusts at speeds above 50mph and the new Transit has also been fitted with lane departure warnings, road sign recognition and a six-inch touchscreen for the sat nav.

Ford's SYNC voice control and connectivity system has also been installed on the new van, as has automatic cruise control and the option of a six speed auto gearbox which will be available later in the year.

The new EcoBlue engine is a four cylinder, two litre diesel available with three power settings of 105, 130 and 170bhp.

It's to be produced at Ford's Dagenham engine plant and will eventually take the place of the Duratorq diesels which were jointly developed with the PSA group, the makers of Peugeot and Citroen models.

Not only is the EcoBlue more powerful than the 2.2-litre block - up 15 horsepower in the case of the 170bhp engine - it also produces much more torque giving the latest Transits added bite, especially at lower speeds.

Fuel economy is said to be improved by almost 15 per cent and having just sampled each of the new EcoBlue engines in a variety of Transits, they all showed their mettle.

The 170bhp engine in the Transit Custom was impressively bang on the money when it came to fuel efficiency and returned an average of 46.1mpg on a 50 mile motorway and country lane route in Germany.

With stop/start fitted to help economy and an injector system so precise it squirts in fuel in globules no bigger than a grain of sugar, the new breed of engine showed plenty of potential and none of them failed to average less than 36 to the gallon.

With the previous engine - officially rated at around 37mpg - you'd be lucky to keep it above 30mpg.

To help reduce NOX emissions the engine comes with a 21 litre AdBlue reservoir which has a range of 6,000 miles between top ups.

Eventually, Ford plans to produce the EcoBlue engine with power outputs ranging from 100 to 240bhp and all will be hooked up to a high performance turbocharger that includes a turbine fashioned out of the same alloy used in rocket motors. A 1.5-litre EcoBlue engine is already in the pipeline.

Prices for the new Transit range - which will be distinguished from the previous models by a silver strip across the front apron below the grille - will start from £20,075 for the short wheelbase 250 model with the 105bhp engine up to £28,425 for the 170bhp version fitted to the flagship Sportvan.

That's an increase of between £950 and £1,400 but that has to be tempered not only with the engineering improvements and added extras but also with reduced running costs and variable service intervals now extended by up to 6,000 miles to 37,000 miles over two years.

Ford calculates that adds up to a fuel cost saving of £1,250 over 80,000 miles for the new 105bhp Transit Custom compared to the previous 100bhp model.

That's nothing to be sneezed at. Just watch the smile on the face of the driver of any of the new vans with the silver strip across the front.